Author Topic: Bad triac?  (Read 3265 times)

Offline ratroder

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Bad triac?
« on: November 26, 2012, »
I seem to be having some issues with triacs this year. I lost 3 on one controller and 1 on another last night. They stick on with the lights lit.

Any suggestions on what is causing this?

Offline jnealand

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Re: Bad triac?
« Reply #1 on: November 26, 2012, »
I had that problem last year.  I've learned to replace them.  I do not know what is causing this.  I still have not turned my lights on this year so I may have another couple to worry about, but I have a lot of unused channels since converting a number of elements to smart strings so I can probably get by.
Jim Nealand
Kennesaw, GA

Offline rrowan

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Re: Bad triac?
« Reply #2 on: November 26, 2012, »
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I seem to be having some issues with triacs this year. I lost 3 on one controller and 1 on another last night. They stick on with the lights lit.

Any suggestions on what is causing this?

Are you lights LED or incandescent ?

Rick R.
Light Animation Hobby - Having fun and Learning at the same time. (21st member of DLA)
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Warning SOME assembly required

Offline tbone321

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Re: Bad triac?
« Reply #3 on: November 26, 2012, »
How much current are you pulling thru them? 
If at first you don't succeed,
your not cut out for sky diving

Offline ratroder

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Re: Bad triac?
« Reply #4 on: November 26, 2012, »
I have replace a few too. It is just annoying.

The reason I even posed something is I have had 4 go bad this year. The triacs will stick on when they go bad. They will be on dim for a while then be full on after a bit. When they are dim they will still receive data and all but will always remain dim when the channel is off.

I am using incandescent mini lights. 400 lights (4 100).

And all my extra channels are used. <md..

Offline Christmasaddict

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Re: Bad triac?
« Reply #5 on: November 26, 2012, »
On a similar note I lost 2 triacs (channels 31 and 32 stuck on)  in one controller last year and managed to replace them after much difficulty.  This year channel 32 stuck on again.  Replacing the opto didn't help so I replaced the triac.  Now channels 31 and 32 will not come on at all.  I think I may have damaged the board with all of my de-soldering on the triacs.  I have become a whiz at soldering but the de-soldering is still giving me fits.  I bought a vacuum tool but it was a waste of money.  Is there any way to diagnose the problem other than replacing the opto and/or the triacs?  Does anyone have any tips for de-soldering?  Boy, it sure would be great if the triacs could be mounted in some sort of socket so they could be easily replaced...

Offline ratroder

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Bad triac?
« Reply #6 on: November 26, 2012, »
When I de-solder them, I cut the triac head (black part) off just leaving the three leads. You can cut the leads short if you want. Then heat the solder joint and pull the lead out through the top. To get rid f the solder just use a de-solder tool. That takes a bit of practice.

Offline Christmasaddict

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Re: Bad triac?
« Reply #7 on: November 26, 2012, »
That is basically what I did.  I cut the triac off and left the 3 leads.  I heated the joints and was able to pull the leads out without much trouble however all of the holes were plugged up with solder.  Getting the holes unplugged was a frustrating experience.  Does anyone have experience using the desoldering wick?  The tool I have just doesn't work well.

Offline tbone321

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Re: Bad triac?
« Reply #8 on: November 26, 2012, »
Which tool are youusing.  The one from the shack works pretty well but you need to give it time to warm up and time to heat up the joint before attempting to suck up the solder.
If at first you don't succeed,
your not cut out for sky diving

Offline Jeffl

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Re: Bad triac?
« Reply #9 on: November 26, 2012, »
A good looking board holder helper also makes it easier. :)  It's hard to hold the soldering iron, solder sucker and the board.  I find this easier and also makes for a quicker job which means less heat and less possibility of messing up a trace.

Offline ratroder

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Re: Bad triac?
« Reply #10 on: November 27, 2012, »
Board holder nah. Vice works well for that.  <fp.

I have a point tip the size of the holes on the board. Put that through from the top and the solder sucker on the back. works well for me. Just have to be careful not to wedge the iron in too far or you will pull the trace off the board.   <md..

Offline Christmasaddict

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Re: Bad triac?
« Reply #11 on: November 27, 2012, »
I think I bought the desoldering tool from Mouser.  It is a suction device that you "cock" and when you push the trigger a spring loaded device pops up and creates a vacuum.  Problem is you can't hold it on the joint when doing this.  It is basically useless.  I have messed with these 2 triacs so much that at least 2 of the "grommets" have detached from the board.  These 2 channels may be toast but I really don't know how to test them.  The interesting thing is that the LED's work normally but therre is no output.

Thankfully I had 4 unused channels on another LE so I was able to move these 2 channels and continue the show at least for this year.

Thanks to everyone for their input and help.

Offline tbone321

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Re: Bad triac?
« Reply #12 on: November 27, 2012, »
You can swap out the opto on one of the channels that doesn't work with one from a channel that does.  Actually, the safer bet is to remove an opto from a working channel and replace it with one from one of the channels that doesn't work.  If the working channel still works, then the problem is either the triac or a bad connection and if it doesn't, then you know that the opto has failed.
If at first you don't succeed,
your not cut out for sky diving

Offline rrowan

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Re: Bad triac?
« Reply #13 on: November 27, 2012, »
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I think I bought the desoldering tool from Mouser.  It is a suction device that you "cock" and when you push the trigger a spring loaded device pops up and creates a vacuum.  Problem is you can't hold it on the joint when doing this.  It is basically useless.  I have messed with these 2 triacs so much that at least 2 of the "grommets" have detached from the board.  These 2 channels may be toast but I really don't know how to test them.  The interesting thing is that the LED's work normally but therre is no output.

Thankfully I had 4 unused channels on another LE so I was able to move these 2 channels and continue the show at least for this year.

Thanks to everyone for their input and help.

I recommend you look at the Radio Shack desolder iron. Best $11.00 I have ever spent.

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oops they raised the price some now $13.00

Rick R.
Light Animation Hobby - Having fun and Learning at the same time. (21st member of DLA)
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Warning SOME assembly required

Offline sebjsan

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Bad triac?
« Reply #14 on: November 27, 2012, »
So the reason I have a led string still on on each of my 2 mega trees is do to a bad trial. Hmm I'll see if I get to it this year.
Sebastian from California